Zn-based materials arise as potential candidates for biodegradable biomedical devices. However, the way of accomplishing proper degradation, mechanical properties and biological behaviour remains uncertain. In this work, structural modification by equal-channel angular pressing (ECAP) or biomimetic coatings on Zn2Ag alloy to control degradation and enhance cell response are investigated.

Zn2Ag alloys were successfully grain refined after undergoing one (E1) and two (E2) ECAP cycles with a 90° internal angle via route BC at RT. UTS and YS decreased from 125 ±1 MPa and 100 ± 7 MPa to 81 ± 3 MPa and 52 ± 4.2 MPa, respectively, after 2 ECAP cycles; and superplasticity was reported. Similar micro-hardness in transversal (46.7 ± 0.7 HV) and longitudinal (45.5 ± 0.8 HV). sections of the E2 suggested isotropic behaviour, also confirmed by the nanoindentation results. Homogeneous degradation behaviour of ECAP processed surfaces was observed from PDP and immersion tests in Hanks' solution, with a calculated corrosion rate by weight difference of approximately 90 mm/yr. Bacterial adhesion was evaluated after 2h and it was detected a decrease of adhered S. Aureus onto the Ag-containing alloys' surfaces compared with inert Ti or pure Zn. The E2 samples showed an excellent antibacterial effect probably due to the homogeneous surface degradation. 

Biomimetic coating was effectively implemented onto Zn2Ag after optimizing PCL coating and subsequently, covalently immobilizing synthetised RGD, REDV linear, and RGD+REDV dual peptides. The PDP and the EIS tests confirmed improved corrosion resistance. HUVEC cell adhesion after 6 h was enhanced onto functionalized surfaces.

The proposed structural or coatings strategies onto Zn2Ag holds great potential to overcome the clinical limitations of current biodegradable metals device.